Intermittent starter problem

[yeesh]

2015 Mercury 150 HP 4 stroke. Starter works intermittently. Driving me crazy. Changed switch, bypassed battery cables and perko with new cables, cleaned all connections. I get a warning beep each time I turn the key on, and yellow wire on solenoid shows 12 volts every time I turn key to start position ( at least 15x in a row) . Cutoff switch checks out OK. Starter clicks each time key is turned, but starter motor only cranks about half the time. I’d assume it’s starter/solenoid assembly but my dealer (who never has a good reason to pass up a sale) said 90% of time, it’s not the starter. Appreciate any ideas. Thanks.

 

[sly_karma]

Top 10 sources of marine electrical problems:
1. bad ground
2. bad ground
3. bad ground
4. bad ground
5. bad ground
6. bad ground
7. bad ground
8. bad ground
9. bad ground
10. something else

Wire brush all connections and terminals, add a smear of dielectric grease before tightening. A further test is to use a set of booster cables to bypass ignition switch. Carefully and repeatedly tap pos booster cable to starter pos terminal, does it arc and turn every time? If the starter is good then there is a test for solenoid function, will be in the engine service manual. If solenoid proves out ok, then that wiring between key and solneoid is to blame. And it'll probably be a bad ground somewhere...

 

[merc850]

1. Are you getting 12v to the starter from the solenoid to the motor if so - 2. try holding the key on and turning the starter motor end around, if the starter motor spins then there's your problem

 

[Scott Danforth]

unbolt the starter and clean the contacts there. look at your cables, if any ends are green, replace the cables.

all connections should be cleaned to shiny metal (clean enough you would let your kids eat with it) and then tightened and sealed with marine electrical varnish.

 

[yeesh]

Thanks for both replies. So we’re thinking either a bad ground somewhere in the system or dead spot on the starter, right? In the meantime, I found several wires from the key switch that seemed to have after market splices- possibly to neutral safety switch. Redid them all. Now (fingers crossed), it seems to work. We’ll see. Tnx again.